Loos J, Koch T, Alvermann A, Bishop A R, Fehske H
Institute of Physics, Academy of Sciences of the Czech Republic, 16200 Prague, Czech Republic.
J Phys Condens Matter. 2009 Sep 30;21(39):395601. doi: 10.1088/0953-8984/21/39/395601. Epub 2009 Sep 1.
To describe the interaction of molecular vibrations with electrons at a quantum dot contacted to metallic leads, we extend an analytical approach that we previously developed for the many-polaron problem. Our scheme is based on an incomplete variational Lang-Firsov transformation, combined with a perturbative calculation of the electron-phonon self-energy in the framework of generalized Matsubara functions. This allows us to describe the system at weak-to-strong coupling and intermediate-to-large phonon frequencies. We present results for the quantum dot spectral function and for the kinetic coefficient that characterizes the electron transport through the dot. With these results we critically examine the strengths and limitations of our approach, and discuss the properties of the molecular quantum dot in the context of polaron physics. We place particular emphasis on the importance of corrections to the concept of an anti-adiabatic dot polaron suggested by the complete Lang-Firsov transformation.
为了描述与金属引线相连的量子点处分子振动与电子的相互作用，我们扩展了一种先前为多极化子问题开发的解析方法。我们的方案基于不完全变分朗-菲尔索夫变换，并结合在广义松原函数框架下对电子-声子自能的微扰计算。这使我们能够描述从弱耦合到强耦合以及从中等频率到高频的声子频率下的系统。我们给出了量子点谱函数和表征电子通过量子点传输的动力学系数的结果。利用这些结果，我们严格审视了我们方法的优点和局限性，并在极化子物理的背景下讨论了分子量子点的性质。我们特别强调了对完全朗-菲尔索夫变换所提出的反绝热点极化子概念进行修正的重要性。
